Shame mercurial didn't catch on. I started learning DVCS' with mercurial, back when they were still a new concept, and git wasn't very good (this is an understatement, git was horrible back then).

What I really liked was the very friendly and usable command line interface, out of the box shortcuts (which I now emulate in my .gitconfig), clear help pages. It was a bit slower than git for enormous projects but it worked wonderfully for me.